Conventionally, a pair of spectacles consists of a spectacles frame in which solar, corrective or fancy lenses are mounted. The spectacles frame comprises a front face, also called a main frame, suitable for receiving said lenses, and two sides mounted to the lateral ends of said front face. Each side is connected to the main frame by the intermediary of a hinge which primarily makes it possible to fold/unfold the side.
In what follows, the terms horizontal and vertical are defined with respect to a spectacles frame in position of use which includes a front face comprised in a vertical plane and longitudinal sides suitable for being unfolded in a horizontal plane, i.e., orthogonally to said front face. In what follows, the term transverse plane is used to designate the plane that is both orthogonal to the horizontal plane and to the vertical plane.
Ordinarily, a hinge comprises a front-face element, a side element and a connecting element connecting said front-face element to said side element in such a way as to allow for a rotation of the side element in relation to the front-face element in the horizontal plane. In other words, each hinge authorises a horizontal rotation in order to fold/unfold the sides of the spectacles in relation to the front face between an open position and a closed position. Such a horizontal rotation is known in prior art and shall not be presented in any further detail. Furthermore, such a hinge makes it possible to authorise an over-opening, which improves its service life.
Moreover, in order to increase the service life of the spectacles frames, it has been proposed to authorise the rotation of the sides of the spectacles in the transverse plane in order to limit the risk of breakage.
To this effect, U.S. Pat. No. 5,596,789A discloses a hinge of the ball-joint type that includes a side element that comprises a guiding sphere mounted in a cage, of complementary shape, connected to the front-face element. Such a ball-joint connection authorises rotations about 3 perpendicular and concurrent axes. Such a hinge is complex and expensive to manufacture due to the machining of spherical surfaces of the ball-joint connection. In addition, the assembly is complex and long to implement.
In order to avoid recourse to spherical surfaces, it is known, via document WO2004067977A1, a hinge that authorises, on the one hand, a rotation in a horizontal plane and, on the other hand, a rotation in a transverse plane. This hinge comprises a front-face element, a side element and a connecting element connecting said front-face element to said side element. The connecting element includes a first portion, having the form of a first hook extending in a transverse plane, which is guided in the front-face element and a second portion, having the form of a second hook extending in a horizontal plane, which is guided in the side element. The first hook and the second hook cooperate together in order to enable a rotation in the horizontal plane and in the transverse plane on their point of contact. In practice, the point of contact between the hooks is mobile according to the orientation of the side. This results in that it is necessary to provide additional means for ensuring the centring between the side element and the front-face element.
Furthermore, such a hinge requires a substantial number of elements, in particular, one or several springs, which are complex to install in the hinge. Moreover, the step of manufacturing hooks, the step of machining hooks guiding openings as well as the step of assembly are long and complex to implement, which increases the cost price of the hinge.
Incidentally, hinges of simple design are known but the latter can be seen from the exterior, which is a disadvantage for users that are increasingly concerned with the aesthetic aspect of their spectacles.
Moreover, U.S. Pat. No. 7,264,349 B1 discloses a spectacles frame whose sides can be removed quickly. However, such a frame does not allow for an over-opening and is not pertinent.
The invention therefore has for purpose to overcome at least some of these disadvantages by proposing a new hinge able to allow for a first rotation about a horizontal plane and a second rotation about a transverse plane. The invention furthermore has for purpose to provide a hinge of simple, aesthetic, and robust design that includes a limited number of elements that are simple to manufacture and to assemble in order to reduce the cost price thereof.